Hydrocarbon alkylation processes employing a phosphorus-modified alumina composite

ABSTRACT

Hydrocarbon conversion processes including hydrocracking and hydrotreating are performed utilizing a novel phosphorus-modified alumina composite comprising a hydrogel having a molar ratio on an elemental basis of phosphorus to aluminum of from 1:1 to 1:100 together with a surface area of about 140 to 450 m 2  /gm. The composite is prepared by admixing an alumina hydrosol with a phosphorus-containing compound to form a phosphorus-modified sol and gelling said admixture.

This is a continuation-in-part of my prior copending application Ser.No. 743,349 filed 11 June, 1985, now U.S. Pat. No. 4,629,717.

BACKGROUND OF THE INVENTION

The present invention relates to a novel phosphorus-modified aluminahydrogel composite and its method of manufacture. The invention alsorelates to the use of the composite, e.g., as a catalyst, or catalystcarrier in a hydrocarbon conversion process.

Alumina spheres useful as a carrier for a catalyst composition can bemanufactured by the oil-drop method. An oil-drop process formanufacturing spherical alumina is taught in U.S. Pat. No. 2,620,314,the teachings of which are incorporated herein by reference. Sphericalalumina is manufactured by the steps of commingling alumina hydrosolwith a gelling agent which is hydrolyzable at an elevated temperature,dispersing the resulting mixture as droplets in a suspending mediumthereby forming hydrogel particles, aging the hydrogel particles,washing with water, drying and calcining.

Phosphorus may be incorporated into catalyst carriers in variousmanners. Canadian Pat. No. 950,439 teaches the addition of a solution ofphosphate ions to an alumina-containing hydrogel. In the specification,patentee defines the term "hydrogel" as an undried gel, precipitatedhydrous oxide, or combinations thereof which are washed free of saltsresulting from the gelation or precipitation reactions. Hydrogels aredistinguished from sols in that the term "sol" refers to colloidaldispersion of polymeric aluminum hydroxide salts which behave as trueliquids.

U.S. Pat. No. 4,066,572 issued to M. E. Choca is pertinent for itsteaching in regard to phospha-alumina gels but relates only toprecipitated gels and not true homogeneous hydrogels. Precipitated gelshave been recognized as not being homogeneous.

U.S. Pat. No. 4,444,962 issued to M. P. McDaniel et al. is alsopertinent for its teaching of a catalyst support formed of aluminumorthophosphate but does not suggest utilization of materials of thealuminum to chloride ratio described herein.

U.S. Pat. No. 4,310,440 issued to S. T. Wilson et al. is pertinent as itrelates to aluminophosphate compositions. The reference, however,describes crystalline materials while the subject invention relates toamorphous materials.

U.S. Pat. No. 2,938,874 issued to E. J. Rosinski describesphosphate-containing alumina gels, but does not suggest utilization ofthe aluminum to chloride ratios disclosed herein and yields a product ofsignificantly different physical characteristics as measured by surfacearea, density and NMR spectra.

Similar to Canadian Pat. No. 950,439, U.S. Pat. No. 4,202,798 disclosesa composite formed by a method which comprises addingphosphorus-containing compounds to an aqueous mixture of hydrousalumina. Hydrous alumina such as gibbsite, bayerite, randomite, etc.,may be prepared by precipitation from an aqueous solution of a solublealuminum salt such as aluminum chloride. The hydrous alumina isdifferent from a sol in that the former is not a liquid colloidalsuspension of aluminum hydroxyl chloride polymer and does not have trueliquid properties.

Another method of utilizing phosphorus in the production of aluminasupports is disclosed in U.S. Pat. No. 3,969,273. In particular, thepatentee adds phosphate ions to a dried alumina gel. No significantchange of nitrogen pore volume was observed.

U.S. Pat. No. 3,879,310 teaches the use of phosphate ions to stabilizepseudo-boehmitic alumina by incorporating the phosphate ion eitherduring the precipitation of the pseudo-boehmitic alumina or by addingthe phosphate ion to freshly precipitated pseudo-boehmitic alumina. Theprecipitation of the pseudo-boehmitic alumina is carried out byinteracting a sodium aluminate solution with aqueous nitric acid.Phosphate ion is added to either of the reactants or simultaneouslyduring the admixture of the sodium aluminate with the nitric acid. Thisphosphate stabilized pseudo-boehmitic alumina has X-ray diffraction peakintensity (l/l_(o)) in the range of 6.5-6.8 Angstroms and contains apseudo-boehmite content of at least 30% by weight.

U.S. Pat. No. 2,890,167 utilizes phosphorus in a reforming catalystcomprising a refractory oxide, halogen and a platinum group metal.Impregnation of the inorganic oxide with a solution of phosphoric acidis suggested as a convenient method of incorporating the phosphorus.

Aluminum phosphate is precipitated onto an alumina gel in U.S. Pat. No.2,441,297 so as to improve the heat stability and mechanical strength ofthe catalyst base prepared in such a manner. Similarly, U.S. Pat. No.2,349,827 teaches the addition of powdered aluminum phosphate to awashed hydrogel. In both cases, the resultant composition contains aphysical mixture of alumina and aluminum phosphate.

U.S. Pat. No. 3,342,750 teaches several methods of producing aluminumphosphate gels. One method involves reacting an aqueous solution ofaluminum chloride and phosphoric acid with ethylene oxide, the amount ofethylene oxide being sufficient to produce gelling to a hydrogel. Thismethod, however, requires the extraction of the hydrogel with an organicwater-soluble extracting agent. The extraction step is necessary toremove carbonaceous material from the hydrogel and increase the surfacearea of the dried and calcined gel.

In another method disclosed in the last-mentioned patent, diluteammonium hydroxide must be slowly added to an aluminumchloride-phosphoric acid solution until the pH of the solution reachesabout 1.0. A hydrogel is then formed by adjusting the pH of the solutionto between 5 and 9 by adding a compound such as ammonium acetate orhexamethylenetetramine. Patentee's hydrogel must then be extracted withan organic water soluble extracting agent to prevent the formation ofthe carbonaceous materials. Patentee points out that it is essentialthat three preparation variables be observed to obtain high surface areaaluminum phosphate gels, namely, (1) very slow addition of NH₄ OH; (2) afinal pH of 5-6; and (3) removal of water by extraction before drying.

The composite of U.S. Pat. No. 3,342,750, though exhibiting high surfacearea at the outset, is hydrothermally unstable (see column 12, lines4-13). Furthermore, the AlPO₄ gel prepared in accordance with themethods disclosed in U.S. Pat. No. 3,342,750 possesses significantcatalytic cracking activity (See Example 10) coupled with a relativelysmall pore diameter.

U.S. Pat. No. 4,210,560 discloses a catalyst support comprisingmagnesia-alumina-aluminum phosphate matrix. In contrast to an "oil drop"gelation procedure, the patentee employs a precipitation procedurewherein aluminum salts, magnesium salts, and phosphoric acid areprecipitated with ammonium hydroxide. Due to the specific method ofprecipitation, the matrix possesses an amorphous morphology.

Finally, U.S. Pat. No. 4,080,311 teaches a thermally stable compositeprecipitate containing aluminum phosphate and alumina having a surfacearea of from about 100 to 200 m² /g. The composite disclosed, however,is an alumina-aluminum phosphate composite precipitate and not a gel.The art has recognized that gels are distinct from precipitates. (SeeWare, J. C., Chemistry of the Colloidal State, Gels, Chapter XII, theteachings of which are incorporated herein).

There have been various attempts to account for and reconcile thedifferences between gels and precipitates. In general, however, a gel isconsidered to be a solidified sol with a high degree of reversibilitybetween the two states. The gel structure is believed to be a capillaryarrangement of fibrils or a "brush heap" which develops from a dispersedphase. The substance, or "fibers", constituting the dispersed phase byway of capillary attraction or adhesion, encloses the liquid phaseforming the gel. The orientation-coalescence formation of a gel is anessential distinction between precipitation and gelation. Inprecipitation, the holding power between the suspension and water isdecreased or destroyed, while in a gel this adhesion remains unimpaired.In any event, the various theories evince basic characteristicdifferences between gels and precipitates.

Kehl, in U.S. Pat. No. 4,080,311, employs an aluminum salt as aluminastarting material and not a colloidal polymeric aluminum sol. Thisdifference in starting material results in the formation of analumina-aluminum phosphate composite precipitate. See column 3, lines14-15. Kehl asserts that the precipitate is a new composition of matterpossessing excellent thermal stability together with relatively highaverage pore radii.

SUMMARY OF THE INVENTION

It has now been discovered that a phosphorus-modified alumina hydrogelcomposite exhibits increased surface area and micropore volume whilemaintaining average pore diameter and decreasing alumina crystallitesize and average bulk density. This novel composite is particularlysuited for use as a catalyst support in hydrocarbon conversion catalyticprocesses offering higher catalyst activity and stability.

The present invention provides hydrocarbon conversion processes whichcomprise contacting a hydrocarbon feedstock at hydrocarbon conversionconditions with a catalyst comprising an amorphous phosphorus-modifiedalumina hydrogel composite having a molar ratio on an elemental basis ofphosphorus to aluminum of from about 1:1 to 1:100 and having a surfacearea of from about 140 to 450 m² /g.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-6 constitute infrared spectra for various alumina compositions.

DETAILED DESCRIPTION OF THE INVENTION

Refractory inorganic oxide particles of spherical shape offer numerousadvantages when employed as a support or carrier material forcatalytically active metallic components. When disposed in a fixed bedin a reaction or contact zone, the spherical particles permit moreuniform packing and reduce the tendency of the reactant stream tochannel through the catalyst bed. When employed in a moving bed type ofoperation, that is, where the particles are transported from one zone toanother by the reactants or an extraneous carrying medium, thespheroidal particles have a further advantage in that there are no sharpedges to break or wear off during processing, thus creating a tendencyto restrict the flow through process equipment.

One preferred method of preparing the refractory inorganic oxide asspheroidal particles is in the gelation of a hydrosol precursor of therefractory inorganic oxide in accordance with the oil-drop method. Saidhydrosols are such as are prepared by the general method whereby an acidsalt of an appropriate metal is hydrolyzed in aqueous solution and thesolution treated at conditions to reduce the acid compound concentrationthereof, as by neutralization. The resulting olation reaction yieldsinorganic polymers of colloidal dimension dispersed and suspended in theremaining liquid. For example, an amorphous alumina hydrosol can beprepared by the hydrolysis of an acid salt of aluminum, such as aluminumchloride, in aqueous solution, and treating said solution at conditionsto reduce the resulting chloride compound concentration thereof, as byneutralization, to achieve an aluminum/chloride compound weight ratiofrom about 0.70:1 to about 1.5:1.

In accordance with the method of the present invention, aphosphorus-containing compound is added to the above-described hydrosolto form a phosphorus-modified hydrosol. Representativephosphorus-containing compounds which may be utilized in the presentinvention include H₃ PO₄, H₃ PO₂, H₃ PO₃, (NH₄)H₂ PO₄, (NH₄)₂ HPO₄, K₃PO₄, K₂ HPO₄, KH₂ PO₄, Na₃ PO₄, Na₂ HPO₄, NaH₂ PO₄, PX₃, RPX₂, R₂ PX, R₃P, X₃ PO, (XO)₃ PO, (XO)₃ P, R₃ PO, R₃ PS, RPO₂, RPS₂, RP(O) (OX)₂,RP(S)(SX)₂, R₂ P(O)OX, R₂ P(S)SX, RP(OX)₂, RP(SX)₂, ROP(OX)₂, RSP(SX)₂,(RS)₂ PSP(SR)₂, and (RO)₂ POP(OR)₂, where R is an alkyl or aryl, such asa phenyl radical, and X is hydrogen, R, or halide. These compoundsinclude primary, RPH₂, secondary, R₂ PH and tertiary, R₃ P phosphinessuch as butyl phosphine, the tertiary phosphine oxides R₃ PO, such astributylphosphine oxide, the tertiary phosphine sulfides, R₃ PS, theprimary, RP(O)(OX)₂, and secondary, R₂ P(O)OX, phosphonic acids such asbenzene phosphonic acid, the corresponding sulfur derivatives such asRP(S)(SX)₂ and R₂ P(S)SX, the esters of the phosphonic acids such asdialkyl phosphonate, (RO)₂ P(O)H, dialkyl alkyl phosphonates, (RO)₂P(O)R, and alkyl dialkyl-phosphinates, (RO)P(O)R₂ ; phosphinous acids,R₂ POX, such as diethylphosphinous acid, primary, (RO)P(OX)₂, secondary,(RO)₂ POX, and tertiary, (RO)₃ P, phosphites, and esters thereof, suchas the monopropyl ester, alkyl dialkylphosphinites, (RO)PR₂ and dialkylalkylphosphinite, (RO)₂ PR, esters. Corresponding sulfur derivates mayalso be employed including (RS)₂ P(S)H, (RS)₂ P(S)R, (RS)P(S)R₂, R₂ PSX,(RS)P(SX)₂, (RS)₂ PSX, (RS)₃ P, (RS)PR₂ and (RS)₂ PR. Examples ofphosphite esters include trimethylphosphite, triethylphosphite,diisopropylphosphite, butylphosphite, and pyrophosphites such astetraethylpyrophosphite. The alkyl groups in the mentioned compoundspreferably contain one to four carbon atoms.

Other suitable phosphorus-containing compounds include ammonium hydrogenphosphate, the phosphorus halides such as phosphorus trichloride,bromide, and iodide, alkyl phosphorodichloridites, (RO)PCl₂,dialkylphosphosphorochloridites, (RO)₂ PCl, dialkylphosphinochloridites,R₂ PCl, alkyl alkylphosphonochloridates, (RO)(R)P(O)Cl,dialkylphosphinochloridates, R₂ P(O)Cl and RP(O)Cl₂. Applicablecorresponding sulfur derivatives include (RS)PCl₂, (RS)₂ PCl,(RS)(R)P(S)Cl and R₂ P(S)Cl.

A 1:1 molar ratio of aluminum to phosphorus in the phosphorus-modifiedsol corresponds to a final calcined spheroidal particle compositioncontaining 24.74 wt. % phosphorus and 20.5 wt. % aluminum, while a 1:100molar ratio corresponds to a final composition of 0.6 wt. % phosphorusand 52.0 wt. % aluminum.

The aluminum chloride hydrosol is typically prepared by digestingaluminum in aqueous hydrochloric acid and/or aluminum chloride solutionat about reflux temperature, usually from about 80° to about 105° C.,and reducing the chloride compound concentration of the resultingaluminum chloride solution by the device of maintaining an excess of thealuminum reactant in the reaction mixture as a neutralizing agent. Thealumina hydrosol is an aluminum chloride hydrosol variously referred toas an aluminum oxychloride hydrosol, aluminum hydroxychloride hydrosol,and the like, such as is formed when utilizing aluminum metal as aneutralizing agent in conjunction with an aqueous aluminum chloridesolution. In any case, the aluminum chloride hydrosol is prepared tocontain aluminum in from about a 0.70:1 to about 1.5:1 weight ratio withthe chloride compound content thereof.

In accordance with the method of invention, phosphorus-modified aluminaparticles are prepared by a method which comprises admixing the aluminahydrosol with a phosphorus-containing compound, the phosphorus toaluminum molar ratio in the resulting phosphorus-modified admixturebeing from 1:1 to 1:100 on an elemental basis and subsequently gellingsaid admixture to obtain said particles.

In one embodiment, gelation is effected by commingling thephosphorus-modified admixture with a gelling agent which is hydrolyzableat an elevated temperature, dispersing said commingled admixture asdroplets in a suspending medium under conditions effective to transformsaid droplets in a suspending medium into hydrogel particles, aging saidhydrogel particles in a suspending medium, washing said hydrogelparticles with water, drying, and calcining said hydrogel particles toobtain phosphorus-modified alumina spheroidal particles.

In another embodiment gelation may be carried out by spray drying theabove-described phosphorus-modified alumina hydrosol or commingling thesubject hydrosol with a gelling agent and then spray drying. Spraydrying may typically be carried out at a temperature of 800° F. (425°C.) to 1400° F. (760° C.) at about atmospheric pressure.

The gelling agent is typically a weak base which, when mixed with thehydrosol, will cause the mixture to set to a gel within a reasonabletime. In this type of operation, the hydrosol is typically set byutilizing ammonia as a neutralizing or setting agent. Usually, theammonia is furnished by an ammonia precursor which is added to thehydrosol. The precursor is suitably hexamethylenetetramine, or urea, ormixtures thereof, although other weakly basic materials which aresubstantially stable at normal temperatures, but decompose to formammonia with increasing temperature, may be suitably employed. It hasbeen found that equal volumes of the hydrosol and of thehexamethylenetetramine solution to alumina sol solution aresatisfactory, but it is understood that this may vary somewhat. The useof a smaller amount of hexamethylenetetramine solution tends to resultin soft spheres while, on the other hand, the use of larger volumes ofbase solution results in spheres which tend to crack easily. Only afraction of the ammonia precursor is hydrolyzed or decomposed in therelatively short period during which initial gelation occurs.

An aging process is preferably subsequently employed. During the agingprocess, the residual ammonia precursor retained in the spheroidalparticles continues to hydrolyze and effect further polymerization ofthe hydrogel whereby desirable pore characteristics are established.Aging of the hydrogel is suitably accomplished over a period of fromabout 1 to about 24 hours, preferably in the oil suspending medium, at atemperature of from about 60° to about 150° C. or more, and at apressure to maintain the water content of the hydrogel spheres in asubstantially liquid phase. The aging of the hydrogel can also becarried out in aqueous NH₃ solution at about 95° C. for a period up toabout 6 hours. Following the aging step, the hydrogel spheres may bewashed with water containing ammonia.

After the hydrogel particles are aged, a drying step is effected. Dryingof the particles is suitably effected at a temperature of from 38° toabout 205° C. Subsequent to the drying step, a calcination step iseffected at a temperature of from about 425° to about 760° C. for 2 to12 hours or more which may be carried out in the presence of steam. Thecalcined particles are useful as is or impregnated with other catalyticcomponents.

The novel phosphorus-modified alumina composite of the present inventionpossesses a high surface area, and a high micropore volume. The novelcomposite is useful as a catalyst support when manufactured inaccordance with the above.

The total pore volume of porous refractory inorganic oxide particleutilized as a catalyst support or carrier material is typicallyexpressed in terms of pore size distribution, that is, in terms of thepore volume attributable to macropores and pore volume attributable tomicropores. As herein contemplated, micropores are those pores having anaverage diameter of less than about 600 Angstroms as determined from theadsorption isotherm for nitrogen at liquid nitrogen temperatures and ata relative pressure (P/P_(o)) of 0.97. The micropore volume will thenconsist of that portion of the total pore volume attributable to poresless than about 600 Angstroms in diameter, and the macropore volume willbe the difference between the total pore volume and the microporevolume. The total pore volume is determined by the mercury intrusionmethod. The total surface area of the refractory inorganic oxideparticles is a function of the micropore volume, substantially all ofthe surface area being associated with pores of less than about 600Angstroms in diameter.

As already mentioned above, according to the present invention it ispossible to manufacture high surface area phosphorus-modified aluminavia the oil-drop method. The surface areas achieved by practice of thepresent invention are substantially greater than the surface area ofconventional gamma-alumina manufactured by the oil-drop method andalumina-aluminum phosphates by precipitation methods. The conventionaloil-dropped alumina possesses a surface area of up to about 250 m² /g.Spheroidal alumina particles manufactured in accordance with the presentinvention possess a surface area of up to about 450 m² /g.

The present invention also provides for a method of controlling thesurface area of the phosphorus-modified composite by varying the amountof phosphorus-containing compounds added to the sol. Further, the degreeof crystallinity of the phosphorus-modified particles can be controlledby varying the amount of phosphorus-containing compound added to thealumina hydrosol which varies the wt. % gamma-alumina in the calcinedparticles as well as the crystallite size. Eventually, as the amount ofphosphorus-containing compound added to the hydrosol is increased andreaches a certain value, the calcined spheres become entirely amorphous,as determined by X-ray diffraction analysis. The material that iscontained in the particles of the present invention that is not in anamorphous phase is present as a crystalline gamma-alumina phase, thus,by controlling the wt. % gamma-alumina present in the particle, thedegree of crystallinity of the particle is, in effect, controlled. Asthe phosphorus content is decreased, the degree of crystallinity isincreased, as measured by the wt. % gamma-alumina via X-ray diffractionanalysis. This is in contrast to the magnesia-alumina-aluminum phosphatematrix disclosed in U.S. Pat. No. 4,210,560 and the alumina-aluminumphosphate matrix disclosed in U.S. Pat. No. 4,080,311 wherein therespective matrices are characterized as amorphous. The presence of awell-controlled amount of gamma-alumina in the composition of thepresent invention is also in contrast to the composition disclosed inU.S. Pat. No. 3,879,310 which contains pseudo-boehmitic alumina.

The present invention also provides for a method of controlling theaverage bulk density of the phosphorus-modified composite by varying theamount of phosphorus-containing compounds added to the hydrosol suchthat, as the quantity of phosphorus increases, the relative average bulkdensity decreases.

The catalytic composite employed in the subject invention mayaccordingly be characterized as a catalytic composite having lowcracking activity and comprising an amorphous phosphorus-modifiedalumina hydrogel having a molar ratio on an elemental basis ofphosphorus to aluminum of from about 1:1 to 1:100 and having a surfacearea of from about 140 to 450 m² /g said hydrogel being formed by thegelation of a homogeneous hydrosol having an aluminum to chloridecompound weight ratio of from about 0.70:1 to 1.5:1. The hydrogelpreferably has a surface area of from about 225 to 450 m² /g and a molarratio of phosphorus to aluminum on an elemental basis of about 1:1.6 to1:100.

The phosphorus-modified alumina particles of the present invention maycontain minor proportions of other well-known refractory inorganicoxides such as silica, titanium dioxide, zirconium dioxide, tin oxide,germanium oxide, chromium oxide, beryllium oxide, vanadium oxide, cesiumoxide, hafnium oxide, zinc oxide, iron oxide, cobalt oxide, magnesia,boria, thoria, and the like materials which can be added to the hydrosolprior to dropping. The finished phosphorus-modified material, which mayhave been dryed and/or calcined, can be crushed to a powder and blendedwith the just listed materials and then formed as by extrusion. Forinstance, oil dropped phosphorus-modified alumina containing a Yzeolite, added to the hydrosol, may be produced as a powder and blendedwith alumina and/or silica alumina to produce a hydrocracking catalystbase to which hydrogenation components are added. The admixture of thephosphorus-modified alumina with a second oxide may therefore result ina total amorphous composite, one having localized regions ofcrystallinity or one having either an amorphous or crystalline matrixsurrounding a dispersion of contrasting material.

In the same manner, crystalline zeolite aluminosilicates can beincorporated into the hydrosol prior to dropping. Typical zeoliteshaving cracking activity which can be suitably dispersed in thephosphorus-modified alumina for use as a catalytic cracking catalyst arewell known in the art. Suitable zeolites are described, for example, inU.S. Pat. No. 3,660,274, incorporated herein by reference. Syntheticallyprepared zeolites are initially in the form of alkali metalaluminosilicates. The alkali metal ions are exchanged with rare earthmetal ions to impart cracking characteristics to the zeolites. Thezeolites are, of course, crystalline, three-dimensional, stablestructures containing a large number of uniform openings or cavitiesinterconnected by smaller, relatively uniform holes or channels. Theeffective pore size of synthetic zeolites is suitably between 6Angstroms and 15 Angstroms in diameter. The overall formula for thezeolites can be represented as follows:

    xM.sub.2/n O:Al.sub.2 O.sub.3 :1.5-150 SiO.sub.2 :YH.sub.2 O

where M is a metal cation and n is its valence and x varies from 0 to 1and y is a function of the degree of dehydration and varies from 0 to 9,M is preferably a rare earth metal cation such as lanthanum, cerium,praseodymium, neodymium, etc., or mixtures of these.

Zeolites which can be employed in combination with this inventioninclude both natural and synthetic zeolites. These zeolites includegmelinite, chabazite, dachiardite, clinoptilolite, faujasite,heulandite, analcite, levynite, erionite, sodalite, cancrinite,nepheline, lazurrite, scolecite, natrolite, offretite, mesolite,mordenite, brewsterite, ferrierite, and the like. Suitable syntheticzeolites which can be treated in accordance with this invention includezeolites X, Y, A, L, ZK-4, B, E, F, HJ, M, Q, T, W, Z, alpha, beta,ZSM-types including ZSM-5 and omega zeolites. The term "zeolites" asused herein contemplates not only aluminosilicates, but substances inwhich the aluminum is replaced by gallium and substances in which thesilicon is replaced by germanium.

The phosphorus-modified alumina particles of the present invention mayalso be used as a support or carrier for catalytic material. In general,these materials will comprise metals or compounds of such metals whichinclude Groups IB, IIA, IIB, IIIB, IVA, IVB, VB, VIB, VIIB and VIII andrare earth Lanthanide series. These metals may be composited eitherprior to, during or after formation of the hydrogel of the presentinvention. Thus, these metals may be added to the hydrosol prior toformation of the hydrogel or impregnated in any suitable manner known inthe art subsequent to the formation of the hydrogel. Such impregnationtechniques would include dip, evaporative and vacuum impregnation.

The metal may be present in the elemental state or any other compoundform such as an oxide or sulfide. Different combinations of the abovemetals may be employed and they may be present alone or in combinationof elemental and/or metal compounds. Preferred metal components and/orcompounds, especially in a hydrotreating catalyst, will comprise metalsfrom Group VIB and Group VIII, the preferred Group VIB metal usuallybeing molybdenum or tungsten and the preferred Group VIII metal usuallybeing nickel or cobalt.

According to one embodiment of the present invention, a hydrocarboncharge stock and hydrogen are contacted with a catalyst composite of thetype described above in a hydrocarbon conversion zone at hydrocarbonconversion conditions. This contacting may be accomplished by using thecatalyst in a fixed bed system, a moving bed system, a fluidized bedsystem, or in a batch type operation; however, in view of the danger ofattrition losses of the valuable catalyst and of well-known operationaladvantages, it is preferred to use a fixed bed system. In this system, ahydrogen-rich gas and the charge stock are preheated by any suitableheating means to the desired reaction temperature and then are passedinto a conversion zone containing a fixed bed of the catalyst typepreviously characterized. It is, of course, understood that theconversion zone may be one or more separate reactors with suitable meanstherebetween to insure that the desired conversion temperature ismaintained at the entrance to each reactor. It is also to be noted thatthe reactants may be contacted with the catalyst bed in either upward,downward, or radial flow fashion with the latter being preferred. Inaddition, it is to be noted that the reactants may be in the liquidphase, a mixed liquid-vapor phase, or a vapor phase when they contactthe catalyst with best results obtained in the vapor phase.

Customary separation procedures may be employed to recover the reactionproducts. For instance, the effluent of a vapor-phase reaction zone maybe subjected to cooling to cause at least partial condensation followedby vapor-liquid separation. A hydrogen-rich vapor produced in thismanner is preferably recycled to the reaction zone while the liquidphase is passed into recovery facilities. Normally the liquid is firstpassed into a stripping column to remove hydrogen and light by-productsduring a petrochemical type process such as alkylation. The bottomsliquid is then fractionated into one or more recycle streams and aheavier (less volatile) product stream. In the case of isomerization,adsorptive-type separation may be employed. In a hydrocracking orhydrotreating embodiment, the liquid from the vapor-liquid separationzone may be passed directly into a primary fractionation column whichproduces the product, light ends and any recycle streams.

The conditions utilized in the numerous hydrocarbon conversionembodiments of the present invention are those customarily used in theart for the particular reaction, or combination of reactions, that is tobe effected. These conditions include a temperature of about 100° F.(38° C.) to 1500° F. (815° C.), a pressure of from atmospheric (101.3kPa) to about 3,000 psig (20,685 kPa gauge), a LHSV (calculated on thebasis of equivalent liquid volume of the charge stock contacted with thecatalyst per hour divided by the volume of conversion zone containingcatalyst) of about 0.1 hr⁻¹ to about 20 hr⁻¹, and hydrogen circulationrates of 1,000 to 50,000 standard cubic feet per barrel of charge (1700to 88,900 std m³ /m³).

In the case of hydrogenation which includes desulfurization anddenitrification, reaction conditions include: a temperature of about200° F. (93° C.)-1000° F. (538° C.), a pressure of atmospheric (101.3kPa) to 3,000 psig (20,685 kPa gauge), a LHSV of about 0.5 hr⁻¹ to 20hr⁻¹, and hydrogen circulation rates of 1,000 to 50,000 s.c.f. perbarrel of charge (1700 to 88,900 std m³ /m³). Likewise, typicalhydrocracking conditions include: a temperature of about 400° F. (205°C.)-1500° F. (815° C.), a pressure of atmospheric (101.3 kPa) to about3,000 psig (20,685 kPa gauge), a LHSV of about 0.1 hr⁻¹ to 15 hr⁻¹, andhydrogen circulation rates of 1,000 to 30,000 s.c.f. per barrel ofcharge (1700 to 53,300 std m³ /m.sup. 3).

The hydrocarbon charge stock subject to hydroconversion in accordancewith the process embodiment of this invention is suitably a petroleumhydrocarbon fraction boiling in the range of from about 400° F. (205°C.) to about 1200° F. (650° C.). The hydrocarbon charge stock is reactedwith an external source of hydrogen at hydroconversion conditions.

Petroleum hydrocarbon fractions which can be utilized as charge stockthus include the gas oils, fuel oils, kerosene, etc., recovered asdistillate in the atmospheric distillation of crude oils, also the lightand heavy vacuum gas oils resulting from the vacuum distillation of thereduced crude, the light and heavy cycle oils recovered from thecatalytic cracking process, light and heavy coker gas oils resultingfrom low pressure coking, coal tar distillates and the like. Residualoils, often referred to as asphaltum oil, liquid asphalt, black oil,residuum, etc., obtained as liquid or semi-liquid residues after theatmospheric or vacuum distillation of crude oils, are operable in thisprocess although it may be desirable to blend such oils with lowerboiling petroleum hydrocarbon fractions for economical operation. Thepetroleum hydrocarbon charge stock may boil substantially continuouslybetween about 400° F. to about 1200° F. (205°-650° C.) or it may consistof any one, or a number of petroleum hydrocarbon fractions, such as areset out above, which distill over within the 400°-1200° F. range.Suitable hydrocarbon feedstocks also include hydrocarbons derived fromtar sand and oil shale.

As is evident from the above discussion, the present invention employsfor a novel phosphorus-modified alumina composite possessing a highsurface area, a low degree of crystallinity character and high microporevolume. Furthermore, the present invention provides for a method ofcontrolling the surface area, ABD, degree of crystallinity andcrystallite size of the particle. The phosphorus-modified aluminacomposite of the present invention, as mentioned above, may be usedeither alone or in combination with refractory oxides and zeolites, as asupport or carrier for catalytic materials. These composites are usefulas hydrocarbon conversion catalysts in hydrocarbon conversion processes.In general, the catalytic materials comprise metals or compounds of suchmetals which include Groups IB, IIA, IIB, IIIB, IVA, IVB, VB, VIB, VIIB,and VIII and rare earth Lanthanide series.

The following examples are presented in illustration of this inventionand are not intended as an undue limitation on the generally broad scopeof the invention as set out in the appended claims.

EXAMPLE I

Appended Table I tabulates various properties of phosphorus-modifiedalumina spherical particles prepared in accordance with the method ofthe present invention and compares the invention particles to the priorart alumina displayed in column 1 of Table I.

Each of the phosphorus-modified alumina spherical particles whoseproperties are tabulated in the table was prepared by a methodsubstantially as set out below.

Metallic aluminum was digested in dilute hydrochloric acid at atemperature of about 102° C. to yield a hydrosol containing polymericalumina hydroxychloride in about 0.88 Al:Cl weight ratio (12.5 wt. %Al). Thereafter, an amount of phosphoric acid calculated to provide therespective phosphorus contents of each calcined spherical particle otherthan the particle used as a control was added to the hydrosol.Appropriate amounts of H₂ O were added in each experiment to maintainalumina and aluminum phosphate solids contents between 25-30%. Eachhydrosol containing phosphorus was then cooled and admixed with aqueoushexamethylenetetramine (HMT) solution to provide a hydrosol containingan HMT to Cl molar ratio of 0.4. The mixture was maintained at 5°-10° C.

The hydrosol was formed into spheroidal hydrogel particles by emittingthe same as droplets into an oil suspending medium contained in adropping tower at about 95° C. The spherical gel particles were aged ina portion of the gas oil for about 1.5 hours at 140° C. and 80 psig (551kPa gauge) pressure. After the aging treatment, the spheres were washedwith water at a temperature of about 95° C. The subsequent drying of thespheres was effected at a temperature of 120° C. for a period of 2hours. Finally, the phosphorus-modified alumina spheres were calcined ata temperature of about 650° C. for about 2 hours in the presence of (3%H₂ O) moist air.

                  TABLE I                                                         ______________________________________                                        Phosphorus-Modified Alumina Spherical Particles Properties                    Sample   1      2       3    4     5    6     7                               ______________________________________                                        Wt. % P  0      1.2     3.3  6.3   15.7 18.5  24.7                            Al:P     ∞                                                                              45:1    15:1 7.3:1 2.3:1                                                                              1.6:1 1:1                             molar ratio                                                                   % γ Al.sub.2 O.sub.3 **                                                          85     75      60   41    4    0     0                               Al.sub.2 O.sub.3                                                                       40     35      34   32    30   *1    *1                              Crystallite                                                                   Size                                                                          Angstroms                                                                     SA m.sup.2 /g                                                                          225    275     349  336   322  242   141                             PV cc/g  0.51   0.61    0.77 0.75  0.69 0.66  0.91                            PD A     91     88      88   89    86   109   258                             ABD g/cc 0.75   0.66    0.59 0.58  0.56 0.56  0.45                            Skeletal 3.5    3.38         2.93  2.67 2.48  2.29                            Density                                                                       ______________________________________                                         *1 indicates that the spherical particles were totally amorphous.             **wt. % as detected by Xray diffraction                                  

Table I shows the effects of varying the amounts of phosphorus additionin accordance with the method of the present invention upon calcinedspherical particles. It is to be noted that the ABD of the calcinedsphere decreases as the phosphorus content of the calcined spheresincreases. The increased phosphorus content of the calcined spheres, ofcourse, implies increased phosphorus-containing compound addition to thehydrosol. The decrease in ABD of the calcined spheres as related to theincrease in phosphorus content of the spheres (or increasedphosphorus-containing compound addition to the hydrosol) is surprisingand unexpected. U.S. Pat. No. 4,008,182 teaches that an increased ratioof metals/acid anion tends to yield particles possessing lower ABDvalues (see column 3, lines 49-53). In contradistinction, it has nowbeen discovered that the addition of phosphorus-containing compounds,e.g., phosphoric acid which decreases the metals/acid anion ratio,results in a decrease of ABD.

Further, it is to be noted that, as the phosphorus content is increased,the skeletal density decreases. This implies the formation of aluminumphosphate as the skeletal density of aluminum phosphate is less thanthat of gamma-alumina.

The significant effects of phosphorus content upon the pore volume,surface area and average pore size are also to be noted. Such effectsare in contradistinction to the observances in U.S. Pat. No. 3,969,273wherein the addition of phosphate to the alumina hydrogel produced nochange in the nitrogen pore volume of final phosphate-containing aluminaproduct over the non-phosphate modified alumina. Further, the averagepore diameter of the aluminum phosphate produced by the method of thepresent invention is substantially greater than the pore diametersachieved in U.S. Pat. No. 3,342,750; compare, for instance, the 258Angstrom pore diameter in the 24.7% P containing support prepared by themethod of the invention versus the pore diameter achieved in the ExampleI of U.S. Pat. No. 3,342,750 of 72 Angstroms. When a commerciallyavailable AlPO₄ was investigated, it was found to possess a surface areaof only 1.66 m² /g and a crystalline structure.

Finally, as shown in Table I, the relationship between the degree ofgamma-alumina crystallinity of the calcined phosphorus-modified spheresand the phosphorus content of the spheres should be noted. The test datashows that the invention provides for a method of decreasing the degreeof crystallinity by increasing the phosphorus content of the calcinedspheres, i.e., increasing the phosphorus-containing compound addition tothe hydrosol.

EXAMPLE II

Infra-red transmission spectra of the phosporus-modified aluminas of thepresent invention were studied. The materials of the present inventiongive rise to certain characteristic absorption bands, namely, at about3450 cm⁻¹, 1650 cm⁻¹, 1100 cm⁻¹, and 500 cm⁻¹ with a shoulder (orinflection) at about 700 cm⁻¹. The absorption band at 1100 cm⁻¹indicates that the existence of a PO₄ ⁻³ configuration in the calcinedphosphorus-modified alumina as AlPO₄. From Example I it is known thatthe AlPO₄ specie in the materials of the present invention possess anamorphous morphology as determined by X-ray diffraction analysis.

FIG. 1 represents an infra-red spectrum of gamma-alumina (Sample 1 ofTable I).

FIG. 2 represents an infra-red spectrum of commercially availablealuminum phosphate not prepared by the method of the present invention.

FIG. 3 represents an infra-red spectrum of phosphorus-modified aluminaspheres prepared by the method of the invention containing 20.5 wt. % Aland 24.7 wt. % P which corresponds to the empirical formula for aluminumphosphate, i.e., a 1:1 Al:P molar ratio.

FIG. 4 represents an infra-red spectrum of phosphorus-modified aluminaspheres containing 18.5 wt. % prepared by the method of the invention.

FIG. 5 represents an infra-red spectrum of phosphorus-modified aluminaspheres containing 6.3 wt. % P prepared by the method of the invention.

FIG. 6 represents an infra-red spectrum of a physical mixture of aluminaand commercially available aluminum phosphate powder.

Interestingly, FIG. 3 shows the infra-red spectrum for aphosphorus-modified alumina sphere of the present invention possessingthe same empirical formula as the commercial aluminum phosphate (seeinfra-red spectrum of FIG. 2), yet the spectra for the two compositionsare different. Note that the infra-red spectrum depicted in FIG. 2 hasan absorption band at about 750 cm⁻¹ which band is not present in thematerials of the present invention. Also, the infra-red spectrum for aphysical mixture of AlPO₄ depicted in FIG. 6 is distinct in that thereis an absorption band at about 750 cm⁻¹. Finally, it should be notedthat the infra-red spectrum for alumina (FIG. 1) possesses a broad bandat 900 to 500 cm⁻¹ which is not characteristic of the absorption spectraof materials produced by the method of the present invention.

EXAMPLE III

The appended Table II sets forth the results of several microreactoractivity tests carried out using materials prepared in accordance withthe present invention (Tests 1 and 2), and a control gamma-aluminamaterial (Test 3). The microactivity tests were performed with anatmospheric pulse reactor. In the experiment, approximately 250 mg of40-60 mesh catalyst was pre-dried in flowing H₂ at 550° C. for 2 hours.The temperature was then lowered to 425° C. in H₂ and a stream of H₂saturated with 1-heptene feed at 0° C. was diverted through the system.Products resulting from conversion of the 1-heptene were hydrogenated.The subsequent product stream was analyzed by gas chromatography. Theproduct distributions in Table II have been tabulated with respect tothe 1-heptene feed.

Note that the phosphorus-modified alumina of the present inventionpossesses an extremely low reactivity at these conditions towards1-heptene. These results are in contrast to results obtained with theAlPO₄ catalyst disclosed in U.S. Pat. No. 3,342,750. Specifically,Example 10 of U.S. Pat. No. 3,342,750 shows that the AlPO₄ gel preparedin accordance with the reference's teachings possesses a high activitywith respect to cracking a gas oil. It is believed that the findings ofthe present 1-heptene microreactor reactivity test are indicative of thehydrocarbon conversion activity of the present invention and that thematerials would possess insignificant cracking ability with respect to agas oil at similar conditions. Test 1, carried out utilizing thephosphorus-modified alumina composite prepared in accordance with thepresent invention, shows virtually no activity with respect to 1-hepteneconversion. The relative inertness of the materials of the presentinvention may, in certain applications, be a desirable quality whenthese materials are employed as catalyst supports or carriers.

                  TABLE II                                                        ______________________________________                                        MICROREACTOR REACTIVITY TEST                                                               Test 1  Test 2                                                                alumina alumina                                                               containing                                                                            containing                                                                              Test 3                                                      24.7% P 3.0% P    γ alumina                                ______________________________________                                        TEMPERATURE (°C.)                                                                     425       425       425                                        INJECTION TIME 21        16        15                                         (MINS.)                                                                       FLOW RATE (cc/MIN.)                                                                          250       250       250                                        % CONVERSION:  7.0       26.4      55.5                                       CRACKING       1.5       1.7       1.7                                        ISOMERIZATION  3.7       20.9      44.2                                       CYCLIZATION    1.8       3.8       9.3                                        ______________________________________                                    

EXAMPLE IV

A sample of AlPO₄ powder was prepared in accordance with theprecipitation method as disclosed in U.S. Pat. No. 2,441,297. Inparticular, 126 grams of aluminum nitrate (Al(NO₃)₃.9H₂ O) weredissolved in 700 ml H₂ O and 45 grams of ammonium phosphate dibasic((NH₄)₂ HPO₄) were dissolved in another 200 ml H₂ O. The above twosolutions were mixed together while stirring and thereafter stirred for1 hour. The solution mixture was allowed to stand undisturbed for 3days. A white powder-like precipitate was filtered from the solution andwashed with about 200 ml of H₂ O . The powder was dried at 100° C. for1/2 hour and subsequently calcined at 600° C. for 3/4 hours. An X-raydiffraction analysis of this white powder yielded the sole presence oforthorhombic AlPO₄ possessing a high degree of crystallinity. This is incontrast to the amorphous phosphorus-modified alumina composite whichcorresponds to the empirical formula for aluminum phosphate, i.e., 1:1Al:P molar ratio which is present in the particles of the presentinvention prepared by an oil-drop gelation procedure.

EXAMPLE V

A direct comparison of the phosphorus-modified alumina composite of thepresent invention was made to the phosphate containing aluminaprecipitate described by Kehl in U.S. Pat. No. 4,080,311. The phosphatecontaining alumina precipitate of the prior art was prepared by thetechnique described in Example 1 of the Kehl patent, U.S. Pat. No.4,080,311, with one exception. After calcination in air at 500° C. for16 hours, the product material was thereafter further calcined at 650°C. for 2 hours rather than at 900° C. for 16 hours as set forth in theexample. The second calcination was conducted at 650° C. for 2 hours inorder to closer approximate the calcination conditions for thephosphorus-modified alumina composite of the present invention. Thedifference in calcination temperatures is not considered crucial sinceKehl teaches a thermally stable composite between calcinationtemperatures of 500° C. to 900° C.

                  TABLE III                                                       ______________________________________                                                      Kehl            Sample 5                                        Composite     U.S. Pat. No. 4,080,311                                                                       Example I                                       ______________________________________                                        Wt. % P       15.7            15.7                                            Wt. % Al      29.9            30.9                                            Wt. % Al.sub.2 O.sub.3                                                                      Amorphous       4                                               (by X-ray defraction)                                                         SA m.sup.2 /g 137             322                                             PV cc/g       0.46            0.69                                            PD (A)        134             86                                              ______________________________________                                    

                  TABLE IV                                                        ______________________________________                                        MICROREACTOR REACTIVITY TEST                                                                          Sample 5                                              Composite       Kehl    Example I                                             ______________________________________                                        Temp. °C.                                                                              549     549                                                   Conversion %    10.4    24.2                                                  Selectivity %                                                                 Cracking        45.2    34.2                                                  Cyclization     10.0    7.8                                                   Isomerization   44.8    58.0                                                  ______________________________________                                    

Table III illustrates various properties of the Kehl composite andSample 5 from Table I of the present specification. Table III shows thatthe surface area of the phosphorus-modified alumina composite of thepresent invention is more than twice that of the Kehl composite eventhough both contain almost identical amounts of phosphorus and aluminum(322 m² /g vs. 137 m² /g). It is noted that, even though the pore radiusof the prepared composite of 67 Angstroms (i.e., 134 A/2=67 A) is lessthan the 75 to 150 Angstrom range taught by the Kehl patent, this minordifference is not the cause of the vast difference in surface area.

In addition, microactivity tests comparing the two composites of Table 3were carried out. 1-heptene was used as the reactant. The tests wereconducted under conditions identical to the microreactivity tests ofExample III except that, after pre-drying, the temperature was loweredto 549° C. Table IV shows that the phosphorus-modified alumina compositeof the present invention has an activity of 1-heptene conversion about2.5 times that of the prepared Kehl composite. In addition, theselectivity toward cracking and isomerization of the two composites isdifferent. The Kehl composite exhibited a much higher hydrocrackingselectivity (45.2%) than the present composite (34.2%). Conversely, thephosphorus-modified alumina composite of the present invention exhibitedhigher isomerization selectivity (58.0%) than the Kehl composite(44.8%). Thus, even at cracking conditions more severe than those ofExample III, the selectivity of the phosphorus-modified aluminacomposite of the present invention, with regards to cracking, is lowerthan exhibited by the prior art.

EXAMPLE VI

The following example illustrates a hydrotreating process employing thephosphorus-modified alumina composite of the present invention. Sample 3from Table I of the present specification was impregnated withmolybdenum and nickel in the following manner. A 44.70 g (0.263 molesMo) sample ammonium dimolybdate (ADM) was dissolved in 120 g of 10.9weight % ammonia solution (prepared by adding 50 ml of concentratedammonium hydroxide to 75 ml of deionized water). After the addition of24.7 ml (0.103 moles Ni) of nickel nitrate solution (15.4% Ni, d=1.59g/ml), the resultant reaction mixture (pH=8.4) was poured onto 141.7 gof the phosphorus-modified alumina composite of the present invention,which was rotating in a 2630 ml glass evaporator. The admixture wascold-rolled for 30 minutes, dried at 100° C. and calcined in a tubefurnace at 950° F. for 2 hours (warm-up time approximately 30 minutes)in the presence of air (1.5 SCFH 0.042 std m³ /h). The finished catalystspecifications are as follows:

    ______________________________________                                        Mo wt. %, (vf)                                                                            12.8     Surface Area, m.sup.2 /g                                                                    196                                        Ni wt. %, (vf)                                                                            3.22     Pore Volume, ml/gr                                                                          0.45                                       P wt. %, (vf)                                                                             2.9      Pore Diameter, A                                                                            92                                         ______________________________________                                    

100 cc of the nickel-molybdenum containing catalyst prepared as abovewas loaded as a single fixed bed. A feedstock blend of coker gas oil andvacuum gas oil, the properties of which are indicated in Table V, waspreheated to 120° C. and contacted with the catalyst bed a downflow LHSVfeed rate of 1.5 hr.⁻¹. The reactor was maintained at a temperature of725° F. (385° C.), a pressure of 800 psig (5,516 kPa gauge) with makeuphydrogen and a total gas recycle of 2,000 standard cubic feet per barrel(3,554 std m³ /m³).

                  TABLE V                                                         ______________________________________                                        FEEDSTOCK SPECIFICATIONS                                                      Density (kg/m.sup.3)                                                                           926.94                                                       °API (60° F.)                                                                    21.0                                                         Specific Gravity 0.9279                                                       Molecular Weight 341                                                          Wt. % N          0.185                                                        Wt. % Basic N    0.066                                                        Wt. % S          2.78                                                         Wt. % C          85.98                                                        Wt. % H          11.78                                                        H/C              1.6                                                          ______________________________________                                    

The reactor effluent was fed to a stripper wherein the gas and liquidproducts were separated. The liquid product was collected and purgedwith nitrogen gas. The gas product was scrubbed with a 15% KOH solutionprior to recycle to the reactor.

                  TABLE VI                                                        ______________________________________                                        LIQUID PRODUCT                                                                Wt. % N (Basic N) 0.013                                                       % HDN (Basic N)   80.3                                                        Wt. % N           0.079                                                       Wt. % HDN         57.3                                                        Wt. % S           0.18                                                        % HDS             93.5                                                        ______________________________________                                    

Table VI lists the nigrogen and sulfur content of the liquid product. Bycomparing Table VI with Table V, it can be seen that the feedstockexperienced 57.3% denitrification (80.3% denitrification as measured byBasic N) and 93.5% desulfurization.

It is contemplated that the subject catalyst can be utilized to performa number of processes other than hydrotreating. These processes includeisomerization of C₄ -C₁₂ paraffins, isomerization of alkylaromatichydrocarbons, alkylation of aromatic hydrocarbons,dehydrocyclodimerization of C₃ and/or C₄ aliphatic hydrocarbons and thealkylation of paraffinic hydrocarbons. The subject invention thereforeincludes such hydrocarbon conversion processes as the alkylation ofbenzene with ethylene to produce ethylbenzene, the alkylation of benzeneor toluene with propylene, the alkylation of benzene with a C₁₀ -C₁₅linear monoolefin to produce linear alkylbenzenes, the alkylation ofisobutane with a butene to produce motor fuel components, and thetransalkylation of toluene and trimethylbenzenes to produce xylenes.These petrochemical processes normally employ a catalyst containing aplatinum group metal.

The catalyst compositions contemplated for usage in these processestherefore normally include a support comprising the phosphorus-modifiedalumina characterized herein plus at least one platinum group metal ormetals such as platinum, platinum and rhodium, palladium, palladium andrhodium or a platinum group metal plus another metal such as eitherplatinum or palladium plus tin. In the case of dehydrocyclodimerization,the preferred metal is gallium. The preferred supports for theseprocesses are high-purity phosphorus-modified alumina, a combination ofthe phosphorus-modified alumina with from 2 to 35 wt. percent of azeolite which is preferably mordenite or a ZSM-5 type zeolite, or acombination of phosphorus-modified alumina with from 5 to 85 wt. % of anunmodified alumina. These processes are performed at the appropriateconversion conditions. For instance, the isomerization of paraffins maybe performed at a temperature of about 150 to about 325 degrees C., aL.H.S.V. of 0.1 to 12.0, a pressure of from 10 to 600 psig and ahydrogen to hydrocarbon mole ratio between 1.0 and 5.0. Alkylationprocesses may be performed with vapor phase, liquid phase or mixed phaseconditions as are well known in the art. Dehydrocyclodimerizationconditions and processing are described in U.S. Pat. No. 4,548,619,which is incorporated herein by reference.

One specific alkylation process of the subject invention is thealkylation of an aromatic hydrocarbon with a C₂ -C₂₀ acyclic olefin.Specific examples are the alkylation of benzene or toluene with ethyleneor propylene. In this instance it is not necessary to provide metals onthe catalyst, although they may be deposited upon the surface modifiedalumina if desired. Alkylation promoting conditions for this processinclude a temperature of from about 240 to 410 degrees C., a pressure offrom 5 to 450 psig (34.5 to 3100 kPa g), a liquid hourly space velocityof 0.5 to 24 and a relative ratio of aromatic:olefin:hydrogen of 1:1:1to 12:1:35. Aromatic to olefinic hydrocarbon ratios above 2:1 arepreferred.

What is claimed is:
 1. An alkylation process which comprises contactinga hydrocarbon feedstock with a catalyst, maintained atalkylation-promoting conditions, comprising an amorphousphosphorus-modified calcined alumina hydrogel composite having a molarratio on an elemental basis of aluminum to phosphorous less than 2.3:1and having a surface area of from about 140 to 450 m² /g.
 2. The processof claim 1 wherein said process is the alkylation of an aromatichydrocarbon with a C₂ -C₂₀ acyclic olefin.
 3. The process of claim 2wherein the olefin is ethylene and the aromatic hydrocarbon is toluene.4. The process of claim 2 wherein the aromatic hydrocarbon is benzene.5. The process of claim 1 wherein the hydrogel is formed by the gelationof a homogeneous hydrosol having an aluminum to chloride compound weightratio of from about 0.7:1 to 1.5:1.
 6. The process of claim 5 whereinthe hydrogel has a micropore volume from about 0.35 to 0.95 cc/g.
 7. Theprocess of claim 6 wherein the average micropore diameter of thehydrogel is from about 40 to 300 A.
 8. The process of claim 7 whereinthe hydrogel possesses absorption bands in the infra-red spectrum atabout 3450 cm⁻¹, 1100 cm⁻¹ with an inflection at about 700 cm⁻¹utilizing the kBr Pellet method.
 9. The process of claim 1 wherein thecatalyst is substantially free of gamma alumina.
 10. The process ofclaim 9 wherein the hydrogel has a molar aluminum to phosphorous ratiobelow 1.6:1.
 11. The process of claim 10 wherein the catalyst comprisesparticles of a crystalline zeolite aluminosilicate which is incorporatedinto the hydrosol prior to the forming of the hydrosol into sphericalform, with the aluminosilicate being chosen from the group consisting ofY zeolites, ZSM-5 zeolites, mordenite and L zeolites.